That enhancement allows my approach to be used with avsc files as well as IDL
files.
Here's our use case.
Project A defines the IDL for a record of type A. Something like this:
**File a.avdl
@namespace("com.example.a")
protocol AService {
record A {
union {null, string} aData = null;
}
Project A provides a jar file with the generated Java classes for A.
Project B creates an IDL that uses type A. Something like this:
**File b.avdl
@namespace("com.example.b")
protocol BService {
import idl "a.avdl"
record B {
union {null, com.example.a.A} a = null;
}
Ideally, Project B doesn't need access to Project A's source code; it will
depend only on the jar file from Project A.
There are two problems. First, the Avro code generator in Project B needs
access to a.avdl in order to satisfy the import in b.avdl, but a.avdl is only
available in project A. Second, the Avro code generator will generate Java
classes for A in Project B, which duplicate the Java files already available in
the jar file in Project A.
My solution is to have Maven package up a.avdl in Project A's source jar. I
then add some Maven-ness to project B to do the following at code generation
time.
1) pull down the sources jar from Project A
2) unpack any avdl files from Project A's sources jar into a "external"
directory under Project B's schema directory
3) run the Avro generator on Project B's schema
4) delete the "external" directory and its contents
5) delete any Java files generated as a result of the avdl files in Project B's
"external" directory
This allows Project B to do something like 'import idl "external/a.avdl"' and
have that external dependency satisfied by Maven at code generation time
without having explicit access to Project A's source.
Dave
-----Original Message-----
From: Doug Cutting [mailto:[email protected]]
Sent: Tuesday, December 11, 2012 2:55 PM
To: [email protected]
Subject: Re: How to handle schema dependencies
On Tue, Dec 11, 2012 at 1:42 PM, Steven Willis <[email protected]> wrote:
> It would be nice if during schema parsing we could specify a classpath
> to be used for dynamic lookup of external schemas
Does AVRO-1188 (included in Avro 1.7.3) help here?
https://issues.apache.org/jira/browse/AVRO-1188
This permits one to specify directories of schemas to import to Avro Maven
executions.
Doug
